In the assembly of various electronic apparatus it is common practice to secure terminating ends of conductors in cables, or one or more pairs of conductors, to terminals of various electronic components or circuit boards mounted within a housing, or in similar apparatus. In such instances, it is desirable to secure intermediate portions of the conductors or the cable to an adjacent wall member of the housing so as to provide strain relief for the terminating ends of the conductors so that any tension that may develop on the conductors or cable will not be transmitted to the terminating ends of the conductors. Preferably, a strain relief device for this purpose should be economical to manufacture, of simplistic design, and capable of being readily assembled and used with a variable number of conductors, including a single conductor pair, as well as a variety of cables having different diameters, without the need for stuffing filler material in and around the conductors.
In the past, a variety of strain relief devices have been proposed to accomplish the foregoing. For example, U.S. Pat. No. 3,788,582 to W. W. Swanguist discloses a connector for connecting non-metallic sheathed cable to an electrical box. The connector includes a tubular body defining a passageway for receiving a cable therethrough and a bisected mounting end which is contractable to permit insertion of the tubular body into an aperture in the electrical box. A rotary rigid cam member, which is journaled in the tubular body, is shaped to permit insertion of a cable through the passageway in the tubular body when the cam member is in a first position. When the cam member is rotated to a second inverted position, the cable is deformed by the cam member into a recess formed in the body in opposed relation to the cam member. The operation of the cam member in this fashion causes the cable to be secured tightly into the clamp and also causes the mounting end of the clamp to expand, thereby locking the clamp into the aperture of the electrical box.